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程序代写案例-ECON10005
时间：2021-11-05
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
HD
EDUCATION
ECON10005
期末复习题
TUTOR: Brandon
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 1
1. 2 simple random samples of mid term and exam marks were obtained for n = 49 students from a semester.
The mid term marks are denoted X1,i and the exam marks X2,i for i = 1, . . . , n. Some sample statistics for
these marks are given below, and can be used to answer the following questions.
(a) Calculate the mean mid term and exam marks for this sample.
(b) Calculate the sample variance and standard deviation of the mid term marks and exam marks. Which
marks are more variable?
(c) Calculate the covariance and correlation between exam and mid term marks. What are the units of
measurements of each of these statistics? Interpret.
(d) Give an estimate of the exam mark a student needed to exceed to be in the top 10% of students on the
exam in the semester.
(e) Calculate the inter-quartile range of mid term marks. What aspect of the marks distribution does this
statistic measure?
Sample statistics for mid term and Exam marks
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 2
2. Define an event A to be a randomly chosen student receives an H1 mark for their assignments. Also define
events N, P and H for the random selected students gets an exam mark in the N range, the P range and the
H range. The joint probability distribution of these events are given by the following table.
N P H
A 0.16 0.29 0.14
Not A 0.25 0.14 0.02
(a) Calculate the marginal probability of the event A and A̅. What is the interpretation of this probability?
(b) Calculate the marginal probabilities of the events N, P and H. What is the most likely grade to have been
received by a student on this exam?
(c) Suppose you are told the randomly chosen student received an H1 mark for the assignments. Using this
information, calculate the new probabilities of the events N, P and H.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
3．Define an event A to be a randomly chosen student receives an H1 mark on their assignments for the
semester. Also define events N, P and H for when the random selected students gets an exam mark in the N
range, the P range and the H range. The conditional probability distributions of the exam events conditional on
the assignment events are given by the following table.
N P H
Conditional on A 0.27 0.49 0.24
Conditional on A bar 0.61 0.34 0.05
You are also told that the marginal probability of a student receiving H1 marks on their assignments is 0.59.
Suppose a randomly drawn student received an H grade on their exam. Using this information, what is the
probability they received H1 for their assignments?
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 3
4. Below is a diagram about the return of 2 firms (i.e. A and B) in different economic environment. Find the
correlation between the returns of 2 firms.
State Probability Firm A Firm B
Good 30% 22% 3%
Normal 40% 10% 5%
Bad 30% -8% 8%
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
5.
Probability Asset A Asset B
Scenarios 1 1/3 4% -5%
Scenarios 2 1/3 -5% 3%
Scenarios 3 1/3 3% 4%
a. Calculate the expected return and standard deviation for each asset, A and B.
b. Now, consider a portfolio of assets A and B, where the investor holds 40% in A and 60% in B. What is the
Standard deviation of this new portfolio?
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 4
6. Suppose that a fair coin is tossed 10 times and the number of heads observed.
a. What is p, the probability that a head is observed when a fair coin is tossed?
b. What are the possible values of the sample proportion of heads in the sample?
c. Determine the probability that the proportion of heads in the sample is more than 0.7.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 5
7. You work in a bank, monitoring the time it takes to process transactions. Let X be the population of all
transaction times. Suppose these are normally distributed with a mean of 2.5 minutes and a standard deviation
of 0.5 minutes:
(a) Can you determine the probability that a randomly selected transaction takes 2 minutes or more? If so, do
so, stating any assumptions that you make. If not, explain why not.
(b) The bank wants to advertise that 67% of transactions take less than a specific number of minutes, x. Can you
show what this value of x is? If so, do so, stating any assumptions that you make. If not, explain why not.
(c) Can you determine the probability that one random sample of size 16 will have a mean of 2.25 minutes or
more? If so, do so, stating any assumptions that you make. If not, explain why not.
8. The time it takes for a laptop to be repaired is normally distributed with an average of 10 working days and a
standard deviation of 2 working days. If a randomly selected person sends their laptop to be repaired, what is
the probability that:
(a) it is repaired in 11 working days or more?
(b) it is repaired in 8 to 12 working days?
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 6
9. A manager notes the distribution of height of students follows an exponential distribution with a mean length
of 5.2 metres and standard deviation of 1.3 metres. If random samples of 70 students are taken to form the
sampling distribution of the sample mean, this sampling distribution can assume to be approximately:(1 分)
A. Binomial with a mean of 5.2 metres and standard error of 0.16 metres.
B. Exponential with a mean of 5.2 metres and a standard error of 0.16 metres.
C. Normal with a mean of 5.2 metres and standard error of 0.16 metres.
D. Poisson with a mean of 5.2 metres and a standard error of 0.16 metres.
10．The central limit theorem assures us that the sampling distribution of the mean
A. is always normal B. approaches normality as the sample size increases
C. none of the above D. is always normal when np and nq>5
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
11. Borachio eats at the same fast-food restaurant every day. Suppose the time X between the moment
Borachio enters the restaurant and the moment he is served his food is normally distributed with mean 4.2
minutes and standard deviation 1.3 minutes.
a. Find the probability that when he enters the restaurant today it will be at least 5 minutes until he is served.
b. Find the probability that average time until he is served in eight randomly selected visits to the restaurant will
be at least 5 minutes.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Hypothesis testing
12. To reduce the number of employee hours lost from accidents, a construction company mandated new
safety equipment. To test effectiveness, a random sample of 50 sites was chosen. The numbers of employee
hours lost in the months before and after the new safety equipment were recorded. The percentage change in
hours lost had a mean of −1.20, with standard deviation of 5.063. Does the new equipment improve safety?
Test the hypothesis in 5% significance level.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
13. An investigator thinks that people under the age of forty have vocabularies that are different than those of
people over sixty years of age. The investigator administers a vocabulary test to a group of 31 younger subjects
and to a group of 31 older subjects. Higher scores reflect better performance. The mean score for younger
subjects was 14.0 and the standard deviation of younger subject's scores was 5.0. The mean score for older
subjects was 20.0 and the standard deviation of older subject's scores was 6.0. Does this experiment provide
evidence for the investigator's theory?
As part of your answer:
a. Please provide, in words, the null and alternative hypotheses.
b. Using an alpha level of 0.05, test the null hypothesis. As part of this test, please compare the actual value for
the appropriate statistic against the critical value(s) for the appropriate statistic.
c. Provide the decision rule for rejecting the null hypothesis, including the critical value(s) for the appropriate
statistic.
d. State your conclusion regarding the results from this test
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
14. An investigator predicts that dog owners in the country spend more time walking their dogs than do dog
owners in the city. The investigator gets a sample of 21 country owners and 23 city owners. The mean number
of hours per week that city owners spend walking their dogs is 10.0. The standard deviation of hours spent
walking the dog by city owners is 3.0. The mean number of hours country owners spent walking their dogs per
week was 15.0. The standard deviation of the number of hours spent walking the dog by owners in the country
was 4.0. Do dog owners in the country spend more time walking their dogs than do dog owners in the city?
As part of your answer...
a. Please provide, in words, the null and alternative hypotheses.
b. Using an alpha level of 0.05, test the null hypothesis. As part of this test, please compare the actual value for
the appropriate statistic against the critical value(s) for the appropriate statistic.
c. Provide the decision rule for rejecting the null hypothesis, including the critical value(s) for the appropriate
statistic.
d. State your conclusion regarding the results from this test
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
15. An investigator theorizes that people who participate in a regular program of exercise will have levels of
systolic blood pressure that are significantly different from that of people who do not participate in a regular
program of exercise. To test this idea the investigator randomly assigns 21 subjects to an exercise program for
10 weeks and 21 subjects to a non-exercise comparison group. After ten weeks the mean systolic blood
pressure of subjects in the exercise group is 137 and the standard deviation of blood pressure values in the
exercise group is 10. After ten weeks, the mean systolic blood pressure of subjects in the non-exercise group is
127 and the standard deviation on subjects in the non-exercise group is 9.0. Please test the investigator's
theory using an alpha level of .05. As part of your answer please...
a. Please provide, in words, the null and alternative hypotheses.
b. Using an alpha level of 0.05, test the null hypothesis. As part of this test, please compare the actual value for
the appropriate statistic against the critical value(s) for the appropriate statistic.
c. Provide the decision rule for rejecting the null hypothesis, including the critical value(s) for the appropriate
statistic.
d. State your conclusion regarding the results from this test
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
16. A company has developed a training program for its entering employees because they have become
concerned with the results of the six-month employee review. They hope that the training program can result in
better six-month reviews. Each trainee constitutes a “pair”, the entering score the employee received when first
entering the firm and the score given at the six-month review. The difference in the two scores were calculated
for each employee and the means for before and after the training program was calculated. The sample mean
before the training program was 20.4 and the sample mean after the training program was 23.9. The standard
deviation of the differences in the two scores across the 20 employees was 3.8 points. Test at the 5% significance
level.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
17. A college football coach was interested in whether the college’s strength development class increased his
players’ maximum lift (in pounds) on the bench press exercise. He asked four of his players to participate in a
study. The amount of weight they could each lift was recorded before they took the strength development
class. After completing the class, the amount of weight they could each lift was again measured. The data are as
follows:
Weight (in pounds) Player1 Player2 Player3 Player4
Amount of weight lifted prior
to the class
205 241 338 368
Amount of weight lifted after
the class
295 252 330 360
The coach wants to know if the strength development class makes his players stronger, on average. Test the
hypothesis in 5% significance level.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
18. Summary statistics of assignment marks (1,) and exam marks (2,), and the individual differences between
those marks ( = 1, − 2,), for a semester are given in the table. A sample of 49 people are selected.
X1 X2 D
Mean 81.3 53.1 28.2
Variance 137.14 277.96 242.54
(a) Let us suppose that the school is introducing a new rule that states that any assessment with average mark
higher than 75 is considered too easily. Carry out a hypothesis test to see if there is the evidence that the
assignments were set too easy. Conduct the test in 5% significance level and using critical value method.
(b) Suppose that another rule that states that any piece of assessment with average mark below 55 is deemed
to have been too difficult. Carry out a hypothesis test to see if there is the evidence that the exams were too
difficult. Use the 5% significance level and a p-value decision rule. The following table of p-values can be
used.
Probability df=48 df=96
2P(t_df>0.798) 0.4359 0.434
P(t_df<-0.798) 0.2179 0.217
P(t_df>0.798) 0.2179 0.217
P(t_df>-0.798) 0.7821 0.783
(c) Carry out a hypothesis test to see if there is evidence that average assignment and exam marks are
different. Justify your choice of test. Conduct the test in 5% significance level and using critical value method.
(d) Calculate a 95% confidence interval for the difference between the assignment and exam marks, and
interpret the interval.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
(0.1764) (0.1843)
Week 10-11
18. A regression analysis was carried out to examine how assignment marks affects average exam marks at the
end of semester. A following conditional equation is drawn to represent the possible relationships between
and . A sample of 49 is selected.
̂ = 1.9762 + 0.6291
(a) Give an interpretation of the coefficient on .
(b) Give an interpretation of the Intercept coefficient. Does this make practical sense? Explain.
(c) Is there evidence that higher assignment marks are associated with higher average exam marks at the end of
semester?
(d) The 2 for this regression is 0.1953. What does this mean?
(e) Compute a 95% confidence interval for the change in average exam marks corresponding to a 1 mark
increase in assignment marks.
(f) Compute a 95% confidence interval for the intercept coefficient.
(g) You are trying to test whether the true intercept coefficient equal to zero. Use the result from (f) to answer.
(h) What is the estimated average exam mark corresponding to an assignment mark of 80%?
(i) What is the correlation coefficient between Exam and Assignment marks?
Assuming the true causal equation was then drawn to represent the causality effect on and
= 1.9802 + 0.6311 +
(j) What does means? What possible factor could include in the calculation of in the scenario given?
学霸联盟
Tutor: Brandon
HD
EDUCATION
ECON10005
期末复习题
TUTOR: Brandon
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 1
1. 2 simple random samples of mid term and exam marks were obtained for n = 49 students from a semester.
The mid term marks are denoted X1,i and the exam marks X2,i for i = 1, . . . , n. Some sample statistics for
these marks are given below, and can be used to answer the following questions.
(a) Calculate the mean mid term and exam marks for this sample.
(b) Calculate the sample variance and standard deviation of the mid term marks and exam marks. Which
marks are more variable?
(c) Calculate the covariance and correlation between exam and mid term marks. What are the units of
measurements of each of these statistics? Interpret.
(d) Give an estimate of the exam mark a student needed to exceed to be in the top 10% of students on the
exam in the semester.
(e) Calculate the inter-quartile range of mid term marks. What aspect of the marks distribution does this
statistic measure?
Sample statistics for mid term and Exam marks
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 2
2. Define an event A to be a randomly chosen student receives an H1 mark for their assignments. Also define
events N, P and H for the random selected students gets an exam mark in the N range, the P range and the
H range. The joint probability distribution of these events are given by the following table.
N P H
A 0.16 0.29 0.14
Not A 0.25 0.14 0.02
(a) Calculate the marginal probability of the event A and A̅. What is the interpretation of this probability?
(b) Calculate the marginal probabilities of the events N, P and H. What is the most likely grade to have been
received by a student on this exam?
(c) Suppose you are told the randomly chosen student received an H1 mark for the assignments. Using this
information, calculate the new probabilities of the events N, P and H.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
3．Define an event A to be a randomly chosen student receives an H1 mark on their assignments for the
semester. Also define events N, P and H for when the random selected students gets an exam mark in the N
range, the P range and the H range. The conditional probability distributions of the exam events conditional on
the assignment events are given by the following table.
N P H
Conditional on A 0.27 0.49 0.24
Conditional on A bar 0.61 0.34 0.05
You are also told that the marginal probability of a student receiving H1 marks on their assignments is 0.59.
Suppose a randomly drawn student received an H grade on their exam. Using this information, what is the
probability they received H1 for their assignments?
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 3
4. Below is a diagram about the return of 2 firms (i.e. A and B) in different economic environment. Find the
correlation between the returns of 2 firms.
State Probability Firm A Firm B
Good 30% 22% 3%
Normal 40% 10% 5%
Bad 30% -8% 8%
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
5.
Probability Asset A Asset B
Scenarios 1 1/3 4% -5%
Scenarios 2 1/3 -5% 3%
Scenarios 3 1/3 3% 4%
a. Calculate the expected return and standard deviation for each asset, A and B.
b. Now, consider a portfolio of assets A and B, where the investor holds 40% in A and 60% in B. What is the
Standard deviation of this new portfolio?
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 4
6. Suppose that a fair coin is tossed 10 times and the number of heads observed.
a. What is p, the probability that a head is observed when a fair coin is tossed?
b. What are the possible values of the sample proportion of heads in the sample?
c. Determine the probability that the proportion of heads in the sample is more than 0.7.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 5
7. You work in a bank, monitoring the time it takes to process transactions. Let X be the population of all
transaction times. Suppose these are normally distributed with a mean of 2.5 minutes and a standard deviation
of 0.5 minutes:
(a) Can you determine the probability that a randomly selected transaction takes 2 minutes or more? If so, do
so, stating any assumptions that you make. If not, explain why not.
(b) The bank wants to advertise that 67% of transactions take less than a specific number of minutes, x. Can you
show what this value of x is? If so, do so, stating any assumptions that you make. If not, explain why not.
(c) Can you determine the probability that one random sample of size 16 will have a mean of 2.25 minutes or
more? If so, do so, stating any assumptions that you make. If not, explain why not.
8. The time it takes for a laptop to be repaired is normally distributed with an average of 10 working days and a
standard deviation of 2 working days. If a randomly selected person sends their laptop to be repaired, what is
the probability that:
(a) it is repaired in 11 working days or more?
(b) it is repaired in 8 to 12 working days?
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Week 6
9. A manager notes the distribution of height of students follows an exponential distribution with a mean length
of 5.2 metres and standard deviation of 1.3 metres. If random samples of 70 students are taken to form the
sampling distribution of the sample mean, this sampling distribution can assume to be approximately:(1 分)
A. Binomial with a mean of 5.2 metres and standard error of 0.16 metres.
B. Exponential with a mean of 5.2 metres and a standard error of 0.16 metres.
C. Normal with a mean of 5.2 metres and standard error of 0.16 metres.
D. Poisson with a mean of 5.2 metres and a standard error of 0.16 metres.
10．The central limit theorem assures us that the sampling distribution of the mean
A. is always normal B. approaches normality as the sample size increases
C. none of the above D. is always normal when np and nq>5
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
11. Borachio eats at the same fast-food restaurant every day. Suppose the time X between the moment
Borachio enters the restaurant and the moment he is served his food is normally distributed with mean 4.2
minutes and standard deviation 1.3 minutes.
a. Find the probability that when he enters the restaurant today it will be at least 5 minutes until he is served.
b. Find the probability that average time until he is served in eight randomly selected visits to the restaurant will
be at least 5 minutes.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
Hypothesis testing
12. To reduce the number of employee hours lost from accidents, a construction company mandated new
safety equipment. To test effectiveness, a random sample of 50 sites was chosen. The numbers of employee
hours lost in the months before and after the new safety equipment were recorded. The percentage change in
hours lost had a mean of −1.20, with standard deviation of 5.063. Does the new equipment improve safety?
Test the hypothesis in 5% significance level.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
13. An investigator thinks that people under the age of forty have vocabularies that are different than those of
people over sixty years of age. The investigator administers a vocabulary test to a group of 31 younger subjects
and to a group of 31 older subjects. Higher scores reflect better performance. The mean score for younger
subjects was 14.0 and the standard deviation of younger subject's scores was 5.0. The mean score for older
subjects was 20.0 and the standard deviation of older subject's scores was 6.0. Does this experiment provide
evidence for the investigator's theory?
As part of your answer:
a. Please provide, in words, the null and alternative hypotheses.
b. Using an alpha level of 0.05, test the null hypothesis. As part of this test, please compare the actual value for
the appropriate statistic against the critical value(s) for the appropriate statistic.
c. Provide the decision rule for rejecting the null hypothesis, including the critical value(s) for the appropriate
statistic.
d. State your conclusion regarding the results from this test
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
14. An investigator predicts that dog owners in the country spend more time walking their dogs than do dog
owners in the city. The investigator gets a sample of 21 country owners and 23 city owners. The mean number
of hours per week that city owners spend walking their dogs is 10.0. The standard deviation of hours spent
walking the dog by city owners is 3.0. The mean number of hours country owners spent walking their dogs per
week was 15.0. The standard deviation of the number of hours spent walking the dog by owners in the country
was 4.0. Do dog owners in the country spend more time walking their dogs than do dog owners in the city?
As part of your answer...
a. Please provide, in words, the null and alternative hypotheses.
b. Using an alpha level of 0.05, test the null hypothesis. As part of this test, please compare the actual value for
the appropriate statistic against the critical value(s) for the appropriate statistic.
c. Provide the decision rule for rejecting the null hypothesis, including the critical value(s) for the appropriate
statistic.
d. State your conclusion regarding the results from this test
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
15. An investigator theorizes that people who participate in a regular program of exercise will have levels of
systolic blood pressure that are significantly different from that of people who do not participate in a regular
program of exercise. To test this idea the investigator randomly assigns 21 subjects to an exercise program for
10 weeks and 21 subjects to a non-exercise comparison group. After ten weeks the mean systolic blood
pressure of subjects in the exercise group is 137 and the standard deviation of blood pressure values in the
exercise group is 10. After ten weeks, the mean systolic blood pressure of subjects in the non-exercise group is
127 and the standard deviation on subjects in the non-exercise group is 9.0. Please test the investigator's
theory using an alpha level of .05. As part of your answer please...
a. Please provide, in words, the null and alternative hypotheses.
b. Using an alpha level of 0.05, test the null hypothesis. As part of this test, please compare the actual value for
the appropriate statistic against the critical value(s) for the appropriate statistic.
c. Provide the decision rule for rejecting the null hypothesis, including the critical value(s) for the appropriate
statistic.
d. State your conclusion regarding the results from this test
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
16. A company has developed a training program for its entering employees because they have become
concerned with the results of the six-month employee review. They hope that the training program can result in
better six-month reviews. Each trainee constitutes a “pair”, the entering score the employee received when first
entering the firm and the score given at the six-month review. The difference in the two scores were calculated
for each employee and the means for before and after the training program was calculated. The sample mean
before the training program was 20.4 and the sample mean after the training program was 23.9. The standard
deviation of the differences in the two scores across the 20 employees was 3.8 points. Test at the 5% significance
level.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
17. A college football coach was interested in whether the college’s strength development class increased his
players’ maximum lift (in pounds) on the bench press exercise. He asked four of his players to participate in a
study. The amount of weight they could each lift was recorded before they took the strength development
class. After completing the class, the amount of weight they could each lift was again measured. The data are as
follows:
Weight (in pounds) Player1 Player2 Player3 Player4
Amount of weight lifted prior
to the class
205 241 338 368
Amount of weight lifted after
the class
295 252 330 360
The coach wants to know if the strength development class makes his players stronger, on average. Test the
hypothesis in 5% significance level.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
18. Summary statistics of assignment marks (1,) and exam marks (2,), and the individual differences between
those marks ( = 1, − 2,), for a semester are given in the table. A sample of 49 people are selected.
X1 X2 D
Mean 81.3 53.1 28.2
Variance 137.14 277.96 242.54
(a) Let us suppose that the school is introducing a new rule that states that any assessment with average mark
higher than 75 is considered too easily. Carry out a hypothesis test to see if there is the evidence that the
assignments were set too easy. Conduct the test in 5% significance level and using critical value method.
(b) Suppose that another rule that states that any piece of assessment with average mark below 55 is deemed
to have been too difficult. Carry out a hypothesis test to see if there is the evidence that the exams were too
difficult. Use the 5% significance level and a p-value decision rule. The following table of p-values can be
used.
Probability df=48 df=96
2P(t_df>0.798) 0.4359 0.434
P(t_df<-0.798) 0.2179 0.217
P(t_df>0.798) 0.2179 0.217
P(t_df>-0.798) 0.7821 0.783
(c) Carry out a hypothesis test to see if there is evidence that average assignment and exam marks are
different. Justify your choice of test. Conduct the test in 5% significance level and using critical value method.
(d) Calculate a 95% confidence interval for the difference between the assignment and exam marks, and
interpret the interval.
HD EDUCATION ECON10005 期末复习题
Tutor: Brandon
(0.1764) (0.1843)
Week 10-11
18. A regression analysis was carried out to examine how assignment marks affects average exam marks at the
end of semester. A following conditional equation is drawn to represent the possible relationships between
and . A sample of 49 is selected.
̂ = 1.9762 + 0.6291
(a) Give an interpretation of the coefficient on .
(b) Give an interpretation of the Intercept coefficient. Does this make practical sense? Explain.
(c) Is there evidence that higher assignment marks are associated with higher average exam marks at the end of
semester?
(d) The 2 for this regression is 0.1953. What does this mean?
(e) Compute a 95% confidence interval for the change in average exam marks corresponding to a 1 mark
increase in assignment marks.
(f) Compute a 95% confidence interval for the intercept coefficient.
(g) You are trying to test whether the true intercept coefficient equal to zero. Use the result from (f) to answer.
(h) What is the estimated average exam mark corresponding to an assignment mark of 80%?
(i) What is the correlation coefficient between Exam and Assignment marks?
Assuming the true causal equation was then drawn to represent the causality effect on and
= 1.9802 + 0.6311 +
(j) What does means? What possible factor could include in the calculation of in the scenario given?
学霸联盟
